ZnO/MgO containing ZnO nanoparticles as a highly effective heterogeneous base catalyst for the synthesis of 4H-pyrans and coumarins in [bmim]BF4
作者:H. Valizadeh、A. A. Azimi
DOI:10.1007/bf03246209
日期:2011.3
4H-Pyrans and coumarins were synthesized through one-pot reactions using ZnO/MgO solid sample containing ZnO nanoparticles as an efficient reusable catalyst in ionicliquid, [bmim]BF4. The catalyst is inexpensive and readily available, stable and storable, easily recycled and reused for several cycles with consistent activity. The procedure offers advantages in terms of high yields, short reaction
Imidazolium-Based Phosphinite Ionic Liquid (IL-OPPh<sub>2</sub>) as Reusable Catalyst and Solvent for the Knoevenagel Condensation Reaction
作者:Hassan Valizadeh、Hamid Gholipour
DOI:10.1080/00397910903097310
日期:2010.4.26
task-specific ionic liquid (IL, OPPh2) that bears a phosphinite weak Lewis base group in an imidazolium cation was found to efficiently catalyze the Knoevenagel condensation of arylaldehydes with malononitrile, dimethyl(diethyl)malonate, and ethylcyanoacetate. This IL plays a dual role as both the reaction media and also catalyst, and it can be easily recovered and reused in several runs. Satisfactory results
One-Pot Wittig and Knoevenagel Reactions in Ionic Liquid as Convenient Methods for the Synthesis of Coumarin Derivatives
作者:Hassan Valizadeh、Sevil Vaghefi
DOI:10.1080/00397910802573163
日期:2009.4.7
condensation, higher conversions were observed via Wittigreaction of these compounds with 2-hydroxybenzaldehyde derivatives and triphenylphosphine. Other 2-hydroxybenzaldehyde derivatives, methyl- and ethylchloroacetates, were reacted in ionic liquids to afford simple coumarins in good yields. These reactions widen the applicability of ionic liquid in organic synthesis.
Cycloadditions of o-quinone dimethides with p-quinol derivatives: regiocontrolled formation of anthracyclic ring systems
作者:Junhua Wang、Liping H. Pettus、Thomas R.R. Pettus
DOI:10.1016/j.tetlet.2003.12.114
日期:2004.2
Regioselective cycloadditions between the cyclohexadienones 12–14 and the ortho-quinone dimethide 19, which is thermally generated from the corresponding 1,3-dihydro-1-methoxy-2,2-dioxide benzo[c]thiophene 27, are reported. The synthetic sequence provides rapid access to highly substituted anthracyclic system and may be of use for construction of the natural product (+)-rishirilide B.
Diastereoselective Dearomatization of Resorcinols Directed by a Lactic Acid Tether: Unprecedented Enantioselective Access to <i>p-</i>Quinols
作者:Lupe H. Mejorado、Christophe Hoarau、Thomas R. R. Pettus
DOI:10.1021/ol0498592
日期:2004.5.1
An operationally simple oxidative dearomatization of resorcinol derivatives is reported that employs an inexpensive chiral directing group. The method provides access to a variety of p-quinol derivatives in good yield and diastereoselectivity. A short reductive process affords 4-hydroxy-4-alkylcyclohexenone derivatives in excellent yields and enantiomeric excesses.